US4719092A - Reduction of nitrogen-based pollutants through the use of urea solutions containing oxygenated hydrocarbon solvents - Google Patents
Reduction of nitrogen-based pollutants through the use of urea solutions containing oxygenated hydrocarbon solvents Download PDFInfo
- Publication number
- US4719092A US4719092A US06/784,828 US78482885A US4719092A US 4719092 A US4719092 A US 4719092A US 78482885 A US78482885 A US 78482885A US 4719092 A US4719092 A US 4719092A
- Authority
- US
- United States
- Prior art keywords
- effluent
- urea
- process according
- solution
- oxygenated hydrocarbon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
- B01D53/56—Nitrogen oxides
Definitions
- the present invention relates to improvements in the combustion of carbonaceous fuels, and more particularly to improvements in firing large boilers with reduced emissions of nitrogen-based pollutants.
- Carbonaceous fuels burn more completely, with reduced emissions of carbon monoxide and unburned hydrocarbons, at oxygen concentrations and combustion air/fuel ratios which permit optimized high flame temperatures.
- these temperatures are above 2000° F. and typically from about 2200° F. to 3000° F.
- these high temperatures and hot spots of higher temperature tend to result in the production of thermal NO x --the temperatures being so high that free radicals of nitrogen and oxygen are formed and chemically combine as nitrogen oxides (NO x ).
- the flame temperature can be lowered to reduce NO x formation by the use of large excesses air or fuel, or a hybrid of both processes known as staged combustion.
- staged combustion a hybrid of both processes known as staged combustion.
- these approaches create excessive carbon-based pollutants.
- Lyon discloses a non-catalytic system for reducing nitrogen monoxide (NO) in a combustion effluent.
- Lyon discloses that ammonia and specified ammonia precursors or their aqueous solutions, can be injected into the effluent for mixing with the nitrogen monoxide at a temperature within the range of 1600° F. to 2000° F.
- a reducing agent can be mixed with the effluent to permit the reduction reaction to occur at temperatures as low as 1300° F., thereby assuring avoidance of high temperature oxidation of ammonia to nitrogen monoxide.
- Lyon discloses that hydrogen is preferred as compared to aromatic, parafinic and olefinic hydrocarbons and oxygenated hydrocarbons, and discloses nothing with regard to the control of ammonia in the final effluent.
- Williamson discloses the purification of acid gas-containing streams at low temperatures approaching ambient. Williamson discloses contacting the gas stream with an amine vapor in sufficient concentration such that its partial pressure is at least 5% of the total pressure of the gas stream. This system thus requires large amounts of the treating gas and does not address the issue of ammonia gas in the final effluent.
- Arand et al disclose the non-catalytic urea reduction of nitrogen oxides in fuel-rich combustion effluents. They indicate that under fuel-rich conditions, aqueous solutions of urea at concentrations of greater than 10%, and preferably greater than 20%, are effective nitrogen oxide reducers at temperatures in excess of 1900° F. This is the effluent from staged combustion which results in the production of high levels of carbonaceous pollutants.
- the present invention provides a process for reducing the concentration of nitrogen oxides in an oxygen-rich effluent from the combustion of a carbonaceous fuel while maintaining low levels of ammonia therein.
- the process comprises injecting an aqueous solution of urea and an oxygenated hydrocarbon into said effluent at an effluent temperature above 1600° F.
- a preferred embodiment of the invention provides for introducing a dilute aqueous solution of the urea and the oxygenated hydrocarbon at a plurality of injection points utilizing droplets having a Sauter mean diameter within the range of from about 50 to about 10,000 microns to achieve uniform mixing of the urea and the oxygenated hydrocarbon with the effluent gas.
- the effluents can be at temperatures in excess of 2000° F.
- urea and other compounds equivalent in effect.
- the compounds are ammonium carbonate, ammonium formate, ammonium oxalate, ammonium hydroxide and various stable amines including hexamethylenetetramine, and mixtures of these.
- reference in this disclosure to urea should not be taken as limiting to urea itself but should extend to urea and all of its equivalents.
- the term equivalent is not limited to exact equivalents, and various materials within the listing of equivalents will be optimally operable at some conditions which are different than those for other of the listed materials. Moreover, some of the materials may be more effective than others.
- the urea is preferably supplied to the effluent as an aqueous solution, and its concentration in the solution will be at least effective to reduce the level of NO x in the effluent.
- the solution can be varied from saturated to very dilute. At higher effluent temperatures, the concentration of urea will be more dilute, say less than 20% at 2000° F., and from 0.5% to 10% at these or higher temperatures. On the other hand, concentrations of from 20% to 40% are more typical for temperatures below 2000° F.
- the concentration of the urea within the effluent gas should be sufficient to provide a reduction in nitrogen oxide levels.
- the urea will be employed at a molar ratio of urea to the baseline nitrogen oxide level of from about 1 to 4 to about 5 to 1, and will more preferably be within the range of from about 2 to 1 to about 1 to 2.
- oxygenated solvents are low molecular weight ketones, aldehydes and mono, di or polyhydric alcohols of aliphatic hydrocarbons having one to four carbons.
- Ethylene glycol is a preferred oxygenated hydrocarbon for this purpose.
- Mixtures of polyols, such as those mixtures of low molecular weight polyols known as hydrogenated starch hydrolysates, can also be employed.
- the level of oxygenated hydrocarbon solvent employed should, at a minimum, be an amount effective to reduce the level of free ammonia in the effluent, and can be employed as a total replacement for water.
- the oxygenated hydrocarbon will be employed at a level of at least about 10% by weight of the urea in solution.
- Weight ratios of ethylene glycol to urea will be within the range of from about 1:4 to 4:1, and preferably closer to unity, e.g., 1:2 to 2:1. These weight ratios apply to other oxygenated solvents as well, which can be employed in combination if desired.
- the urea solution will often, of necessity, be dispersed within the effluent gas stream at a point where the effluent is at a temperature above 2000° F.
- Large industrial boilers of the type employed for utility power plants and other large facilities will typically be water jacketted and have access only at limited points. In the most typical situation, the boiler interior can be accessed only through burner access ports and at access ports above the flame, where the temperatures at full load are typically within the range of from about 2050° F. to about 2600° F.
- the temperature at this point of access will typically fall within the range of from about 2100° F. to about 2600° F., and when fired with coal or oil, will typically fall within the range of about 2050° F. to 2400° F. These temperatures will not permit the effective introduction of solid urea or urea solutions as previously disclosed to the art.
- the urea solutions according to the present invention are preferably injected at a number of spaced points where there is sufficient turbulence to distribute the droplets throughout the effluent.
- the solutions are injected from nozzles which are effective to uniformly form and disperse droplets of the solutions within the flowing effluent stream.
- the nozzles are located at a sufficient number of points to achieve uniform mixing.
- the size of the droplets of solution will be within the range of from about 10 to about 10,000, and preferably be greater than about 50 microns.
- the droplet size is important to enable uniform mixing of the urea with the effluent and penetration of the urea sufficiently along the internal boiler path that it can achieve its intended function.
- the size of the droplets will preferably be increased with increasing temperature. At temperatures below 200° F., droplet sizes of less than 150 microns are quite effective, while at higher temperatures the droplets should be larger, and preferably larger than 500 microns.
- the following example describes the reduction of nitrogen oxide with control of ammonia levels in the effluent from a commercial utility boiler system.
- test runs and the data recorded therefrom are set forth in the following table.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
Priority Applications (11)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/784,828 US4719092A (en) | 1985-10-04 | 1985-10-04 | Reduction of nitrogen-based pollutants through the use of urea solutions containing oxygenated hydrocarbon solvents |
DE8686906556T DE3687656T2 (de) | 1985-10-04 | 1986-10-03 | Ermaessigung stickstoffhaltiger schadstoffe durch verwendung von sauerstoffhaltiges kohlenwasserstoffloesungsmittel aufweisendem harnstoffloesungen. |
AU65249/86A AU592386B2 (en) | 1985-10-04 | 1986-10-03 | Reduction of nitrogen-based pollutants through the use of urea solutions containing oxygenated hydrocarbon solvents |
PCT/US1986/002098 WO1987002024A1 (fr) | 1985-10-04 | 1986-10-03 | Diminution des polluants a base d'azote par l'emploi de solution d'uree contenant des solvants d'hydrocarbure oxygene |
AT86906556T ATE85032T1 (de) | 1985-10-04 | 1986-10-03 | Ermaessigung stickstoffhaltiger schadstoffe durch verwendung von sauerstoffhaltiges kohlenwasserstoffloesungsmittel aufweisendem harnstoffloesungen. |
JP61505543A JPH07100131B2 (ja) | 1985-10-04 | 1986-10-03 | 酸素含有炭化水素溶媒を含む尿素溶液を使用する,窒素ベ−スの汚染物質の削減 |
DE198686906556T DE242394T1 (de) | 1985-10-04 | 1986-10-03 | Ermaessigung stickstoffhaltiger schadstoffe durch verwendung von sauerstoffhaltiges kohlenwasserstoffloesungsmittel aufweisendem harnstoffloesungen. |
EP86906556A EP0242394B1 (fr) | 1985-10-04 | 1986-10-03 | Diminution des polluants a base d'azote par l'emploi de solution d'uree contenant des solvants d'hydrocarbure oxygene |
CA000519895A CA1255475A (fr) | 1985-10-04 | 1986-10-06 | Reduction des polluants azotes par l'utilisation de solutions d'uree contenant des solvants d'hydrocarbure oxygene |
US07/108,779 US4844878A (en) | 1985-10-04 | 1987-10-14 | Process for the reduction of nitrogen oxides in an effluent |
DD88320784A DD275620A5 (de) | 1985-10-04 | 1988-10-14 | Verfahren zur verringerung der konzentration an stickoxiden in einem abstrom |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/784,828 US4719092A (en) | 1985-10-04 | 1985-10-04 | Reduction of nitrogen-based pollutants through the use of urea solutions containing oxygenated hydrocarbon solvents |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US07/108,779 Continuation-In-Part US4844878A (en) | 1985-10-04 | 1987-10-14 | Process for the reduction of nitrogen oxides in an effluent |
Publications (1)
Publication Number | Publication Date |
---|---|
US4719092A true US4719092A (en) | 1988-01-12 |
Family
ID=25133654
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/784,828 Expired - Lifetime US4719092A (en) | 1985-10-04 | 1985-10-04 | Reduction of nitrogen-based pollutants through the use of urea solutions containing oxygenated hydrocarbon solvents |
Country Status (9)
Country | Link |
---|---|
US (1) | US4719092A (fr) |
EP (1) | EP0242394B1 (fr) |
JP (1) | JPH07100131B2 (fr) |
AT (1) | ATE85032T1 (fr) |
AU (1) | AU592386B2 (fr) |
CA (1) | CA1255475A (fr) |
DD (1) | DD275620A5 (fr) |
DE (2) | DE3687656T2 (fr) |
WO (1) | WO1987002024A1 (fr) |
Cited By (40)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4851201A (en) * | 1987-04-16 | 1989-07-25 | Energy And Environmental Research Corporation | Methods of removing NOx and SOx emissions from combustion systems using nitrogenous compounds |
EP0326943A2 (fr) * | 1988-02-02 | 1989-08-09 | KRC Umwelttechnik GmbH | Procédé et dispositif pour la réduction d'oxydes d'azote utilisant une injection de chaudière à deux étages |
WO1989007982A1 (fr) * | 1988-02-26 | 1989-09-08 | Fuel Tech, Inc. | Procede et injecteur reduisant la concentration de polluants dans un effluent |
US4927612A (en) * | 1985-10-04 | 1990-05-22 | Fuel Tech, Inc. | Reduction of nitrogen- and carbon-based pollutants |
US4978514A (en) * | 1989-09-12 | 1990-12-18 | Fuel Tech, Inc. | Combined catalytic/non-catalytic process for nitrogen oxides reduction |
US4985218A (en) * | 1989-03-03 | 1991-01-15 | Fuel Tech, Inc. | Process and injector for reducing the concentration of pollutants in an effluent |
US4997631A (en) * | 1990-03-07 | 1991-03-05 | Fuel Tech, Inc. | Process for reducing nitrogen oxides without generating nitrous oxide |
US5048432A (en) * | 1990-12-27 | 1991-09-17 | Nalco Fuel Tech | Process and apparatus for the thermal decomposition of nitrous oxide |
US5078982A (en) * | 1990-09-20 | 1992-01-07 | Molecular Technology Corporation | Reduction of nitrogen oxide in effluent gases using formaldehyde |
US5087431A (en) * | 1990-09-20 | 1992-02-11 | Molecular Technology Corporation | Catalytic decomposition of cyanuric acid and use of product to reduce nitrogen oxide emissions |
US5171554A (en) * | 1990-09-20 | 1992-12-15 | Molecular Technology Corporation | Conversion of formaldehyde and nitrogen to a gaseous product and use of gaseous product in reduction of nitrogen oxide in effluent gases |
US5171558A (en) * | 1990-09-20 | 1992-12-15 | Molecular Technology Corporation | Catalytic decomposition of cyanuric acid and use of product to reduce nitrogen oxide emissions |
US5192515A (en) * | 1990-09-20 | 1993-03-09 | Molecular Technology Corporation | Reduction of nitrogen oxide and carbon monoxide in effluent gases |
US5229090A (en) * | 1991-07-03 | 1993-07-20 | Nalco Fuel Tech | Process for nitrogen oxides reduction to lowest achievable level |
US5234670A (en) * | 1990-09-20 | 1993-08-10 | Molecular Technology Corporation | Reduction of nitrogen oxide in effluent gases using NCO radicals |
US5234671A (en) * | 1990-09-20 | 1993-08-10 | Molecular Technology Corporation | Reduction of nitrogen oxide in effluent gases using formaldehyde and/or formaldehyde-derived free radicals |
US5240689A (en) * | 1989-06-19 | 1993-08-31 | Noell, Inc. | Process using two-stage boiler injection for reduction of nitrogen |
US5262138A (en) * | 1989-08-31 | 1993-11-16 | Union Oil Company Of California | Process for NOx abatement |
WO1994008895A1 (fr) * | 1992-10-13 | 1994-04-28 | Nalco Fuel Tech | Procede et composition destines a reduire la pollution |
WO1994008893A1 (fr) * | 1992-10-13 | 1994-04-28 | Nalco Fuel Tech | Procede et composition destines a la lutte contre la pollution |
US5342599A (en) * | 1990-09-14 | 1994-08-30 | Cummins Power Generation, Inc. | Surface stabilized sources of isocyanic acid |
US5342592A (en) * | 1989-07-04 | 1994-08-30 | Fuel Tech Europe Ltd. | Lance-type injection apparatus for introducing chemical agents into flue gases |
WO1994026659A1 (fr) * | 1993-05-07 | 1994-11-24 | Nalco Fuel Tech | PROCEDE ET APPAREIL POUR AMELIORER LA REPARTITION DE PRODUITS CHIMIQUES REDUISANT LE NOx DANS UN ENVIRONNEMENT A HAUTE TENEUR EN MATIERES SOLIDES |
US5404841A (en) * | 1993-08-30 | 1995-04-11 | Valentine; James M. | Reduction of nitrogen oxides emissions from diesel engines |
US5462718A (en) * | 1994-06-13 | 1995-10-31 | Foster Wheeler Energy Corporation | System for decreasing NOx emissions from a fluidized bed reactor |
US5478542A (en) * | 1992-11-23 | 1995-12-26 | Nalco Fuel Tech | Process for minimizing pollutant concentrations in combustion gases |
US5543123A (en) * | 1990-08-01 | 1996-08-06 | Nalco Fuel Tech | Low pressure formation of a urea hydrolysate for nitrogen oxides reduction |
US5658547A (en) * | 1994-06-30 | 1997-08-19 | Nalco Fuel Tech | Simplified efficient process for reducing NOx, SOx, and particulates |
US5681536A (en) * | 1996-05-07 | 1997-10-28 | Nebraska Public Power District | Injection lance for uniformly injecting anhydrous ammonia and air into a boiler cavity |
US5728357A (en) * | 1996-04-10 | 1998-03-17 | Nalco Fuel Tech | Reduction of NOx emissions from rotary cement kilns by selective noncatalytic reduction |
US5985222A (en) * | 1996-11-01 | 1999-11-16 | Noxtech, Inc. | Apparatus and method for reducing NOx from exhaust gases produced by industrial processes |
US6001152A (en) * | 1997-05-29 | 1999-12-14 | Sinha; Rabindra K. | Flue gas conditioning for the removal of particulates, hazardous substances, NOx, and SOx |
US6258336B1 (en) | 1995-06-09 | 2001-07-10 | Gas Research Institute | Method and apparatus for NOx reduction in flue gases |
US6280695B1 (en) | 2000-07-10 | 2001-08-28 | Ge Energy & Environmental Research Corp. | Method of reducing NOx in a combustion flue gas |
US6436359B1 (en) | 2000-10-25 | 2002-08-20 | Ec&C Technologies, Inc. | Method for controlling the production of ammonia from urea for NOx scrubbing |
US20030109047A1 (en) * | 2001-11-09 | 2003-06-12 | Valentine James M. | Continuously-variable control of pollution reducing chemicals for combustion sources |
US20080291965A1 (en) * | 2007-05-18 | 2008-11-27 | Environmental Energy Services, Inc. | Method for measuring ash/slag deposition in a utility boiler |
US20090148370A1 (en) * | 2007-12-06 | 2009-06-11 | Spencer Iii Herbert W | Process to produce ammonia from urea |
US9586831B2 (en) | 2014-06-09 | 2017-03-07 | Wahlco, Inc. | Urea to ammonia process |
US11027237B2 (en) | 2019-07-19 | 2021-06-08 | American Electric Power Company, Inc. | Direct injection of aqueous urea |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4844878A (en) * | 1985-10-04 | 1989-07-04 | Fuel Tech, Inc. | Process for the reduction of nitrogen oxides in an effluent |
AU585670B2 (en) * | 1985-10-04 | 1989-06-22 | Fuel Tech. Inc. | Reduction of nitrogen- and carbon-based pollutants through the use of urea solutions |
US4830839A (en) * | 1987-02-13 | 1989-05-16 | Fuel Tech, Inc. | Ammonia scrubbing |
US5192338A (en) * | 1987-09-03 | 1993-03-09 | Commonwealth Scientific And Industrial Research Organisation | Coal ash modification and reduction |
ZA886518B (en) * | 1987-09-03 | 1989-05-30 | Commw Scient Ind Res Org | Coal ash modification and reduction |
AT390208B (de) * | 1988-05-09 | 1990-04-10 | Waagner Biro Ag | Verfahren zur entfernung von stickoxiden |
US5457223A (en) * | 1992-10-09 | 1995-10-10 | The Standard Oil Company | Process for elimination of waste material during manufacture of acrylonitrile |
CA2141734C (fr) * | 1995-01-25 | 2000-06-06 | Raj Narain Pandey | Reduction catalytique selective d'oxydes d'azote |
DE10021517C1 (de) * | 2000-05-03 | 2002-01-10 | Kuelps Heinz Juergen | Zurückdrängung und Verminderung der Hochtemperatur-Halogen-Korrosion in Verbrennungsanlagen durch den Einsatz von Wirkstoffen sowie Wirkstoff-Mischungen |
EP2138766B1 (fr) * | 2008-06-23 | 2016-03-30 | Hitachi Zosen Inova AG | Procédé destiné à l'injection d'une matière dans une cuvette d'une installation d'incinération des déchets |
FR2941869B1 (fr) * | 2009-02-10 | 2013-03-29 | Novergie | Procede de reduction des oxydes d'azote issus de la combustion des combustibles solides |
JP5812630B2 (ja) * | 2011-03-02 | 2015-11-17 | 三菱重工環境・化学エンジニアリング株式会社 | 廃棄物焼却プラント |
CN102721797B (zh) * | 2011-09-22 | 2014-11-05 | 辽宁省电力有限公司 | 无烟煤在热解中生成HCN/NH3与在锅炉中燃烧生成NOx的关联性的分析方法 |
KR102104050B1 (ko) * | 2019-05-21 | 2020-04-24 | 오미혜 | 질소산화물 저감용 조성물 및 질소산화물을 저감시키는 방법 |
Citations (6)
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US3900554A (en) * | 1973-03-16 | 1975-08-19 | Exxon Research Engineering Co | Method for the reduction of the concentration of no in combustion effluents using ammonia |
JPS514588A (ja) * | 1974-07-01 | 1976-01-14 | Hitachi Ltd | Dohakanjitsusohoho |
US4208386A (en) * | 1976-03-03 | 1980-06-17 | Electric Power Research Institute, Inc. | Urea reduction of NOx in combustion effluents |
US4325924A (en) * | 1977-10-25 | 1982-04-20 | Electric Power Research Institute, Inc. | Urea reduction of NOx in fuel rich combustion effluents |
US4507269A (en) * | 1983-11-10 | 1985-03-26 | Exxon Research & Engineering Co. | Non-catalytic method for reducing the concentration of NO in combustion effluents by injection of ammonia at temperatures greater than about 1300 degree K |
US4624840A (en) * | 1983-11-10 | 1986-11-25 | Exxon Research & Engineering Company | Non-catalytic method for reducing the concentration of NO in combustion effluents by injection of ammonia at temperatures greater than about 1300° K. |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU6408086A (en) * | 1985-10-04 | 1987-04-24 | Fuel Tech. Inc. | Reduction of nitrogen- and carbon-based pollutants |
-
1985
- 1985-10-04 US US06/784,828 patent/US4719092A/en not_active Expired - Lifetime
-
1986
- 1986-10-03 DE DE8686906556T patent/DE3687656T2/de not_active Revoked
- 1986-10-03 JP JP61505543A patent/JPH07100131B2/ja not_active Expired - Lifetime
- 1986-10-03 AT AT86906556T patent/ATE85032T1/de not_active IP Right Cessation
- 1986-10-03 DE DE198686906556T patent/DE242394T1/de active Pending
- 1986-10-03 EP EP86906556A patent/EP0242394B1/fr not_active Revoked
- 1986-10-03 WO PCT/US1986/002098 patent/WO1987002024A1/fr not_active Application Discontinuation
- 1986-10-03 AU AU65249/86A patent/AU592386B2/en not_active Ceased
- 1986-10-06 CA CA000519895A patent/CA1255475A/fr not_active Expired
-
1988
- 1988-10-14 DD DD88320784A patent/DD275620A5/de not_active IP Right Cessation
Patent Citations (6)
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US3900554A (en) * | 1973-03-16 | 1975-08-19 | Exxon Research Engineering Co | Method for the reduction of the concentration of no in combustion effluents using ammonia |
JPS514588A (ja) * | 1974-07-01 | 1976-01-14 | Hitachi Ltd | Dohakanjitsusohoho |
US4208386A (en) * | 1976-03-03 | 1980-06-17 | Electric Power Research Institute, Inc. | Urea reduction of NOx in combustion effluents |
US4325924A (en) * | 1977-10-25 | 1982-04-20 | Electric Power Research Institute, Inc. | Urea reduction of NOx in fuel rich combustion effluents |
US4507269A (en) * | 1983-11-10 | 1985-03-26 | Exxon Research & Engineering Co. | Non-catalytic method for reducing the concentration of NO in combustion effluents by injection of ammonia at temperatures greater than about 1300 degree K |
US4624840A (en) * | 1983-11-10 | 1986-11-25 | Exxon Research & Engineering Company | Non-catalytic method for reducing the concentration of NO in combustion effluents by injection of ammonia at temperatures greater than about 1300° K. |
Cited By (51)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4927612A (en) * | 1985-10-04 | 1990-05-22 | Fuel Tech, Inc. | Reduction of nitrogen- and carbon-based pollutants |
US4851201A (en) * | 1987-04-16 | 1989-07-25 | Energy And Environmental Research Corporation | Methods of removing NOx and SOx emissions from combustion systems using nitrogenous compounds |
EP0326943A2 (fr) * | 1988-02-02 | 1989-08-09 | KRC Umwelttechnik GmbH | Procédé et dispositif pour la réduction d'oxydes d'azote utilisant une injection de chaudière à deux étages |
EP0326943A3 (fr) * | 1988-02-02 | 1990-05-16 | KRC Umwelttechnik GmbH | Procédé et dispositif pour la réduction d'oxydes d'azote utilisant une injection de chaudière à deux étages |
WO1989007982A1 (fr) * | 1988-02-26 | 1989-09-08 | Fuel Tech, Inc. | Procede et injecteur reduisant la concentration de polluants dans un effluent |
US4985218A (en) * | 1989-03-03 | 1991-01-15 | Fuel Tech, Inc. | Process and injector for reducing the concentration of pollutants in an effluent |
US5240689A (en) * | 1989-06-19 | 1993-08-31 | Noell, Inc. | Process using two-stage boiler injection for reduction of nitrogen |
US5342592A (en) * | 1989-07-04 | 1994-08-30 | Fuel Tech Europe Ltd. | Lance-type injection apparatus for introducing chemical agents into flue gases |
US5399326A (en) * | 1989-08-31 | 1995-03-21 | Union Oil Company Of California | Process for noncatalytic NOx abatement |
US5262138A (en) * | 1989-08-31 | 1993-11-16 | Union Oil Company Of California | Process for NOx abatement |
WO1991004224A1 (fr) * | 1989-09-12 | 1991-04-04 | Fuel Tech, Inc. | Procede combine catalytique/non catalytique de reduction des oxydes azotes |
US4978514A (en) * | 1989-09-12 | 1990-12-18 | Fuel Tech, Inc. | Combined catalytic/non-catalytic process for nitrogen oxides reduction |
US4997631A (en) * | 1990-03-07 | 1991-03-05 | Fuel Tech, Inc. | Process for reducing nitrogen oxides without generating nitrous oxide |
US5543123A (en) * | 1990-08-01 | 1996-08-06 | Nalco Fuel Tech | Low pressure formation of a urea hydrolysate for nitrogen oxides reduction |
US5342599A (en) * | 1990-09-14 | 1994-08-30 | Cummins Power Generation, Inc. | Surface stabilized sources of isocyanic acid |
US5171554A (en) * | 1990-09-20 | 1992-12-15 | Molecular Technology Corporation | Conversion of formaldehyde and nitrogen to a gaseous product and use of gaseous product in reduction of nitrogen oxide in effluent gases |
US5234670A (en) * | 1990-09-20 | 1993-08-10 | Molecular Technology Corporation | Reduction of nitrogen oxide in effluent gases using NCO radicals |
US5234671A (en) * | 1990-09-20 | 1993-08-10 | Molecular Technology Corporation | Reduction of nitrogen oxide in effluent gases using formaldehyde and/or formaldehyde-derived free radicals |
US5192515A (en) * | 1990-09-20 | 1993-03-09 | Molecular Technology Corporation | Reduction of nitrogen oxide and carbon monoxide in effluent gases |
US5171558A (en) * | 1990-09-20 | 1992-12-15 | Molecular Technology Corporation | Catalytic decomposition of cyanuric acid and use of product to reduce nitrogen oxide emissions |
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Also Published As
Publication number | Publication date |
---|---|
CA1255475A (fr) | 1989-06-13 |
AU6524986A (en) | 1987-04-24 |
EP0242394B1 (fr) | 1993-01-27 |
EP0242394A4 (fr) | 1988-10-27 |
DE3687656D1 (de) | 1993-03-11 |
EP0242394A1 (fr) | 1987-10-28 |
ATE85032T1 (de) | 1993-02-15 |
DE242394T1 (de) | 1988-02-25 |
DD275620A5 (de) | 1990-01-31 |
JPH07100131B2 (ja) | 1995-11-01 |
WO1987002024A1 (fr) | 1987-04-09 |
DE3687656T2 (de) | 1993-05-19 |
JPS63502087A (ja) | 1988-08-18 |
AU592386B2 (en) | 1990-01-11 |
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